- The evidence
- Family-based approach
- Tailoring programmes
- Determining whether a child is overweight or obese
- Referring on to specialist services
- Children and young people with special needs
- Encouraging adherence to programmes
- Behaviour-change techniques
- Increasing uptake of programmes
- Training and support
- Sustaining behaviour changes
- Monitoring, evaluation and setting outcome measures
- Economic considerations
The Programme Development Group (PDG) took account of a number of factors and issues when developing the recommendations, as follows. Please note: this section does not contain recommendations. (See Recommendations.)
3.1 The PDG highlighted the need for greater consistency in reported outcome measures and the time points at which they are recorded, to allow for better comparison of the effectiveness and cost effectiveness of interventions.
3.2 In many studies, there was a lack of detail on the content of the intervention. This made it difficult to compare different approaches or methods and to determine which elements of 'multi-component' interventions contribute to overall effectiveness.
3.3 Review 1 included studies from the UK, Western Europe, North America, Australia and New Zealand, because the potential applicability of the findings to the UK was considered to be high. The UK evidence included some lower quality, relatively small, uncontrolled studies. However, such studies were valuable in indicating a general 'direction of travel' in terms of the effectiveness of interventions.
3.4 Limited data were available for children and young people of specific ages. No studies were found in which children younger than 6 were specifically targeted. Although several programmes had a lower age limit (of between 3 and 5 years), none of the studies provided data separately for this age group. Most programmes aimed at very young children appeared to be aimed at all children, rather than those who were overweight or obese. Study participants were predominantly female. Only 2 studies included more boys than girls and, in most cases, there were at least 20% more girls than boys. However, the PDG noted from expert testimony and experience that, in the 'real world', there tends to be a more even mix of boys and girls among programme participants. Nevertheless, the importance of identifying barriers to involving more boys in intervention studies was noted.
3.5 There were limited and contradictory data on the impact of lifestyle weight management programmes according to socioeconomic group. In most studies, children and young people were from middle-income families. In the 2 UK studies that did have significant numbers from low-income families, no association was found between outcomes and socioeconomic group. However, a US study found that participation led to greater reductions in BMI z scores among those from higher income families.
3.6 No data were available on the effectiveness or cost effectiveness of lifestyle weight management services for children and young people with special needs. Nor were any data available on the barriers and facilitators to implementing lifestyle weight management services for this group. The PDG noted this gap in the evidence base and has made recommendations for research in this area.
3.7 Review 1 considered the reported follow-up data for participants in the included studies. It did not consider any secondary prevention or weight maintenance programmes for children or young people who have previously been obese or overweight. There is also a lack of information on the views of those who do not take part or who drop out early from a lifestyle weight management programme. This is an important omission, because there is an association between BMI adjusted for age and sex (BMI z score) at baseline and drop-out rates. It is possible, therefore, that review 2 may not have fully captured the views of children and young people with higher BMI scores. Review 2 focused on the views of children, young people and their families about weight management programmes. It did not capture their views or experiences of the referral process.
3.8 There is strong evidence from review 1 to suggest that targeting both parents and children, or whole families, is effective in reducing BMI z scores by the end the programme. In addition, the evidence on interventions involving families showed no negative effects on wellbeing and, in some cases, showed positive effects.
3.9 A report commissioned for the PDG identified that it is more common for adolescents to attend programmes alone, or for parental attendance to be optional. That is despite evidence showing that parental or family involvement contributes to success in weight management. The recommendations for a whole-family approach therefore apply to older children and adolescents. However, the PDG acknowledged that flexibility is important as young people and older children become more independent, because some young people and some older children may prefer to attend separate sessions from their parents or carers. (This might be on a group or an individual basis.)
3.10 Many overweight and obese children and young people may have, or come from a family with, a history of failed attempts to manage their weight. The Group noted the importance of exploring this shared history, along with family attitudes towards diet, physical activity and the amount of time spent being sedentary.
3.11 Efforts to manage a child or young person's weight are not always supported, and are sometimes undermined, by members of the wider family. This is possibly because of a lack of understanding of the aims of lifestyle weight management programmes and the importance of managing the weight of obese or overweight children and young people. The PDG was aware that some family members may not attend the programme with the child or young person. (This may be true for non-resident parents, step-parents and grandparents.) With this in mind the Group noted the importance of gaining the wider family's understanding and support and has made a recommendation to this effect.
3.12 The PDG noted that lifestyle weight management programmes were often 'bought in' by commissioners and were rarely tailored to meet local needs. As a result, the recommendations highlight the importance of assessing local needs and ensuring programmes are tailored to address those needs.
3.13 Because of a dearth of evidence, the PDG has been unable to make age-specific recommendations. However, the Group does stress the importance of tailoring programmes according to age and stage of development.
3.14 The PDG did not make specific recommendations for children and young people with severe obesity. However, the Group was aware that some of them may attend a lifestyle weight management programme. For example, families may self-refer to these services, or they may be referred by health professionals following treatment at a specialist obesity service. Or they may attend a lifestyle weight management service (to support lifestyle changes) and also receive individual specialist support. The PDG highlighted the importance of developing an individually tailored plan that includes appropriate goals for all children and young people, including those from this group.
3.15 The PDG recognised that although BMI is a practical estimate of overweight in children and young people, it is not a direct measure of adiposity. It acknowledged that it may be less accurate and need to be interpreted with caution in children and young people who are muscular or in those with earlier than average pubertal development. In addition, the Group was aware that there is evidence that adults from black and minority ethnic groups are at risk of obesity-associated conditions and diseases (comorbidities), such as type 2 diabetes, at a lower BMI than the white European population. However, it was beyond the remit of this guidance to assess whether the same applies to children and young people.
3.16 The PDG recognised that 'complex obesity' (in which someone who is obese also has obesity-associated diseases or conditions [comorbidities]) can occur at any level of obesity (although this is more likely, as BMI increases). That is why the Group recommended the use of a comorbidity assessment tool. The aim was to ensure that, if necessary, children and young people are referred on for specialist support. However, the PDG was unable to identify an appropriate assessment tool for use by lifestyle weight management services. The Group viewed development of such a tool as a priority and made a research recommendation to this effect.
3.17 The PDG heard from expert testimony that overweight and obese children are often victimised and that this can lead to depression. The Group also heard that emotional and behavioural problems and impaired quality of life have been observed in obese pre-school children. Behaviours such as binge eating are also more likely in obese adolescents than in adolescents of a healthy weight. Treatment of these conditions was beyond the scope of this guidance. However, the PDG noted the importance of ensuring that any such potential issues are identified and that the child or young person is referred on for specialist support if necessary.
3.18 The PDG was aware that some children and young people with disabilities, learning difficulties or other special needs may have particular problems managing their weight. This may be because of their underlying condition, or because their physical activity is limited. The PDG also recognised the importance of ensuring they have access to appropriate services to help them manage their weight. In addition, it acknowledged the statutory duty upon public bodies to look at ways of ensuring equal access to services.
3.19 The PDG noted that many overweight or obese children and young people with more complex needs will need the support of a specialist obesity service or other specialist services to help manage their weight. However, members also noted that some providers have developed lifestyle weight management programmes for children and young people with mild to moderate learning difficulties or for disabled children. Others have adapted existing programmes and trained staff to accommodate their needs. The PDG welcomed such approaches and encouraged evaluation of them.
3.20 The PDG was particularly concerned about the practical issues that may prevent potential participants from taking part in, or continuing to attend, a lifestyle weight management programme. This includes the location and type of venue where programmes are delivered and participants' need to accommodate other family commitments.
3.21 Evidence from review 2 highlighted how important it is to ensure the family and the child or young person recognise and accept that they are overweight or obese. Conversely, a lack of recognition or denial that the child or young person is overweight or obese can hinder uptake and adherence to a lifestyle weight management programme. The recommendations reflect this finding, including a recommendation for further research as to how this may be best achieved.
3.22 The PDG debated whether lifestyle weight management services should be offered to groups of families or to families on an individual basis. Evidence shows that both approaches are effective in reducing BMI adjusted for age and sex (BMI z scores). The PDG noted from expert testimony that group sessions can provide a good opportunity to see how others with similar goals have succeeded. They also provide peer support to build the child or young person's self-belief that they, too, can succeed. The PDG acknowledged that individual sessions were likely to be more resource-intensive. However, the Group was aware that some children and young people may not feel able to discuss or address their weight in a group setting. For this reason the PDG recommended flexibility as necessary.
3.23 The PDG heard from expert testimony that behaviour-change techniques are effective in lifestyle weight management programmes for children and young people and are widely used. (This includes self-monitoring, stimulus control and goal-setting.) A 'package' of these techniques is usually included in the programme, because it is not known how much each element contributes to effectiveness. The PDG has therefore made a recommendation for more research in this area.
3.24 The PDG heard that aspects of cognitive behavioural therapy are used by some lifestyle weight management programmes, usually with older children or adolescents. This therapy focuses on understanding unhelpful or inaccurate thought processes, then changing behaviour to encourage new ways of thinking. It is usually delivered by staff who have received specialist training. However, current evidence does not allow conclusions to be drawn on its effectiveness.
3.25 Review 2 identified a lack of awareness of the availability of lifestyle weight management programmes among health professionals. In addition, the former Childhood Obesity National Support Team found that programmes frequently ran below capacity. The PDG was therefore aware of the need to increase both self-referrals and referrals by health professionals – including the need to agree clear referral pathways.
3.26 The PDG identified a wide range of 'actors' who could raise awareness of lifestyle weight management programmes. In particular, the PDG noted that staff conducting the National Child Measurement Programme were in an ideal position to direct parents and carers to these programmes for advice and support.
3.27 The key aims of the Healthy Child Programme: pregnancy and the first 5 years of life include early recognition of risk factors for obesity, prevention and early intervention. The Programme's approach is consistent with this guidance. For example, it recommends working in partnership with the family, setting achievable goals and exploring earlier life experiences in relation to obesity. The PDG recognised the important contribution that staff delivering the Healthy Child Programme could make in raising awareness of, and formally referring children and their families to, lifestyle weight management programmes. It also recognised their potential role in providing ongoing support.
3.28 Review 2 and the former National Support Team for Childhood Obesity findings both highlighted the need to train lifestyle weight management programme staff and health professionals referring people to the programmes.
3.29 The PDG noted that staff may lack the confidence and skills to raise the issue of weight management with potential participants and identified this as a training need. In addition, the National Support Team for Childhood Obesity found that a lack of confidence to deliver weight management interventions was sometimes linked to the programme staffs' own unhealthy weight. The PDG noted the need to offer these staff support to manage their weight.
3.30 The PDG did not make recommendations regarding the optimal length of programmes. A meta-analysis conducted for review 1 showed that the duration of programmes was associated with improved BMI z scores in programmes lasting between 8 and 24 months. However, once the programme was completed, the effect disappeared over time and was non-significant at 6 months after completion. The PDG therefore stressed the importance of ongoing support and follow-up once programmes are completed.
3.31 The PDG has recommended that participants completing programmes are given information about relevant local support services. However, the Group has not made recommendations regarding those services because this is beyond the scope of the guidance. It noted that a number of pieces of NICE guidance have made recommendations in this area (see Related NICE guidance).
3.32 The PDG noted that many lifestyle weight management services for children and young people were often commissioned in isolation and in response to a short-term funding opportunity. The Group highlighted the importance of commissioning these services as part of a wider, more sustainable approach to preventing and treating obesity. This approach is reflected in this guidance. It is also addressed in detail by NICE public health guidance on obesity: working with local communities.
3.33 The PDG noted there had been little robust monitoring and evaluation of lifestyle weight management programmes. The Group also noted that new local authority responsibilities for public health may be an opportunity to embed monitoring requirements into service specifications and contracts. Periodic evaluations into planning and commissioning strategies may also be possible.
3.34 The PDG debated at length the choice of suitable outcome measures for lifestyle weight management programmes for children and young people. The Group agreed that the primary goal, in the longer term, is to reduce BMI for age and sex (BMI z scores). However, it was aware that, in practice, most programmes run for only around 8 to 12 weeks – and substantial reductions in that time may be difficult to achieve.
3.35 A report commissioned for the PDG identified unrealistic outcome measures as a barrier to providers working effectively with commissioners. Nevertheless, the PDG was aware that a reduction in BMI for age and sex is sometimes used by commissioners as a key performance indicator. Financial penalties may, in some cases, be attached to failure of providers to achieve this outcome.
3.36 The PDG recognised that maintaining weight (and preventing further weight gain) is the short-term aim of many lifestyle weight management programmes for children and young people. The rationale is that if the child maintains their weight as they grow in height over time, their BMI will be reduced. The PDG acknowledged that young people who are no longer growing taller will ultimately need to lose weight to improve their BMI. However, the Group also recognised that this takes time. Members considered that an appropriate short-term aim may be to avoid further weight gain while the young person acquires the skills and knowledge they need to make behavioural changes. Over time, as the changes to their behaviour become established, there should be a positive effect on their BMI.
3.37 The PDG felt it was very important to sustain any positive outcomes beyond the duration of a lifestyle weight management programme. Therefore the Group placed an emphasis on sustaining long-term change.
3.38 The PDG recognised the importance of retaining participants in the programme. This is based on evidence that the greater the proportion of total programme sessions a child or young person attends, the more likely they are to succeed. This is reflected in a number of recommendations.
3.39 The economic model defines a child or young person as overweight if their BMI (adjusted for age and sex) lies between the 85th and 95th centiles of the UK 1990 centile chart. These centiles correspond to BMI z scores of 1 and 2 respectively for the UK 1990 centile chart. They are used for defining whether someone is overweight or obese in population studies and for monitoring populations, rather than for the clinical management of individuals. In the model, a child or young person whose BMI (adjusted for age and sex) lies between the 95th and the 99.5th centile is defined as obese; children and young people above the 99.5th centile are described as 'morbidly obese'.
3.40 How the average weight of children of a particular age and sex changes over time can be referred to as their 'weight trajectory'. All other factors being equal, the BMI z score of this group of children will be maintained. So the aim of programmes for overweight or obese children and young people is to help them make changes so that they move to a lower weight trajectory. This might be achieved by: losing weight; by maintaining weight as a child grows in height; or by gaining less weight than would have been expected. In all cases, they will weigh less than would have otherwise been expected over the same time period.
3.41 The economic model estimated that interventions costing £100 per person would usually be cost effective from a public sector perspective. This would be the case if a group of overweight or obese children could be moved to a lower average weight trajectory and this was maintained throughout life. (This is true for a weight loss of as little as 0.5%.) Interventions that permanently lower weight trajectory by an average 3% are estimated to be cost effective, if their average cost is less than £1000 per child.
3.42 The cost effectiveness of interventions for children and young people who are morbidly obese, as defined by the model, was unclear. The PDG concluded that interventions for children who are morbidly obese would need to lower their BMI z score considerably to be worth doing.
3.43 There was little evidence on whether children and young people can maintain for life the lower weight trajectory they may achieve during a lifestyle weight management programme. If they do, the economic model concludes that interventions that cause very small average decreases in weight trajectory will be worth undertaking. However, if the weight is regained quickly and they revert to their previous weight trajectory, then the intervention is estimated not to be cost effective. For example, the model looked at an intervention for overweight boys or girls aged from 12 to 17 that cost an average £437 per person. To be cost effective, their average weight trajectory, following an initial average weight loss of 5% of body weight, must lie below what it would have been without the intervention for at least 11 years.
3.44 If the weight of each participant in a lifestyle weight management programme is reduced by an average of 0.5% – and the post-intervention weight trajectory is maintained for life – the model estimates that interventions costing up to about £500 per child will be cost effective for both girls and boys and for each category of overweight and obesity. Interventions costing £2000 per child are estimated to need weight losses of 3 to 5%, maintained for life, to be cost effective for children who are borderline overweight, but of 2% (maintained for life) for children who are obese or morbidly obese.
3.45 The model assumes a discount rate of 3.5% per year for both costs and health benefits. Most of the health benefits of providing a lifestyle weight management programme for overweight and obese children and young people accrue in the later stages of life. As a result of discounting, these benefits are given a relatively low value compared with a health benefit that is immediate. Reducing the discount rate to 1.5% per year has the effect of increasing the present value of future health benefits considerably, and thus improves cost effectiveness.